This relates to the domain of cellular telecommunications, more precisely in the context of an Internet Packet (IP) Multimedia System (IMS).
In the definition of the IMS Voice over Long Term Evolution (LTE) standard, the User Equipment (UE) Voice Over Internet Packet (VoIP) engine does not take into account the Connected Discontinuous Reception (CDRX) cycle duration or semi-persistent scheduling (SPS) period configured by the cellular network. This lack of synergy between UE cellular data link layer and UE VoIP engine executing the Real-time Transport Protocol (RTP) and scheduling audio data driver read/write and network send/receive does not allow the UE to execute an audio voice call with an optimal latency and power performance.